The skin of the human foot exudes perspiration, as well as odors, in varying degrees, depending upon such factors as temperature of the ambient, the amount of physical activity being performed, and the natural propensity of the particular person to perspire. The comfort and health of the human foot is greatly influenced by the rate of evaporation of the perspiration generated as a result of movement and/or physical exercise. Moreover, it is common for any type of shoe to develop malodorous characteristics with use; a problem which has been acknowledged and addressed with varying degrees of failure in a plethora of ways over the years.
In particular, a number of attempts have been implemented to provide ventilated footwear to enhance both comfort and to obviate the odors commonly associated with shoes and related footwear. For example, U.S. Pat. Nos. 3,012,342 (which issued to E. Ramirez on Dec. 12, 1961, U.S. Pat. No. 4,438,537 (which issued to G. McBarron on Mar. 27, 1984), U.S. Pat. No. 4,499,672 (which issued to S. Kim on Feb. 19, 1985), U.S. Pat. No. 4,654,982 (which issued to K. Lee on Apr. 7, 1987), and U.S. Pat. No. 4,813,160 (which issued to L. Kuznetz on Mar. 21, 1989) illustrate and describe various forms of footwear, including structure provided in the sole of the shoes for allowing the flow of air from outside the shoe to inside the space therewithin, or (as in the case of the Lee patent) for allowing air within the shoe to be exhausted therefrom in use. As can be imagined, care had to be taken with many of these shoes to prevent moisture, dirt and the like from entering the shoe through these ventilation openings in use, and, more importantly, the amount of air flow Provided by these structures was quite limited. The Lee device, in particular, also contemplates the use of mechanical air expiration exhausters which must be carefully fitted within the sole of the shoe, making the construction thereof relatively complex and unwieldy. In practicality, these structures did not Provide appreciable, positive ventilation.
Other attempts at providing ventilation to footwear can be seen in U.S. Pat. Nos. 4,776,110 (which issued to J. Shiang on Oct. 11, 1988), and U.S. Pat. No. 4,835,883 (which issued to E. Tetrault, et al. on June 6, 1989), as well as in the French reference 2,614,510 (filed Apr. 30, 1987). In particular, the Shiang arrangement includes an insole embedded inside a shoe, having an air pumping means in the rear portion of the inside which is activated by the wearer's foot to positively pump air brought into the shoe through a hole formed in the side of the upper portion of the shoe. The air is forced into the front part of the shoe where it is released through a Plurality of perforations formed in the insole of the shoe. A front ventilating hole in the upper portions of the shoe outer is also provided.
Similarly, the Tetrault, et al. shoe includes an associated conduit formed with a check valve for directing ambient air into a ventilating sole formed in the shoe. The ventilating sole includes a plurality of chambers which are separated by generally "V" shaped vane elements which allow movement of air only in a forward direction. Alternate compression and expansion of the insole allows captured air within the various chambers to circulate therewithin and to provide a cushioning effect for the wearer. Likewise the French reference appears to pertain to a structure for providing ventilation to the sole of a shoe, including an air inlet conduit and an air pumping device which might respond to alternate compression by the heel of the wearer's foot to circulate air within the shoe. While these devices attempted to respond to the lack of significant air ventilation provided by the more passive devices discussed above, they are all relatively complex in design and difficult and expensive to manufacture. Moreover, their structures were designed solely to provide for air ventilation within the shoe, were generally not removable or interchangeable, and failed to respond directly to other concerns such as comfort, support, interchangeability, deodorization, and anti-fungus concerns.
Other attempts to provide ventilation to shoes in the form of shoe insoles can be found in U.S. Pat. No. 3,624,930 (which issued to O. Johnson, et al., on Dec. 7, 1971), U.S. Pat. No. 4,224,746 (which issued to S. Kim on Sept. 30, 1980), and U.S. Pat. No. 3,426,455 (which issued to V. Drago on Feb. 11, 1969). The Drago device was contemplated as an insole which was to be bonded to the inner surface of a shoe sole, and included a bottom portion having downwardly facing ribs which increase in depth toward the rear of the insole to provide a wedge-shaped orthopedic insole. The upper layers of the insole are pattern perforated to Provide fluid communication between chambers formed by the ribs on the underside of the insole such that air is periodically expelled from those chambers when the insole is compressed in use. While this compression tends to cause some air movement within the shoe, the amount of ventilation provided by the Drago device is quite limited, and the insole is bonded to the shoe, eliminating convenient removability thereof.
Similarly, the Johnson, et al., insole includes resiliently compressible ribs which face downwardly and rest on the non-porous surface of the sole of the shoe. The ribs are compressed and flattened in response to pressure of the wearer's foot, causing air trapped below the insole to be released upwardly through a plurality of vent holes located near the front portions of the insole. Again, the Johnson insole provides only limited air ventilation within the shoe. The Kim insole includes a resilient member having air inlet holes located near the rear or heel portion, and air outlet or vent holes located near the toe portion of the insole. Kim relies upon the wearer's foot to close off the inlet holes during normal walking activity as downward pressure is applied to the shoe, thereby forcing air trapped within the compressible portion of the insole outwardly adjacent the toe portion of the shoe.
Other ventilated insoles for shoes include pumping devices to provide positive air flow within the shoe. In particular, U.S. Pat. No. 3,225,463 (which issued to C. Burham on Dec. 28, 1965), U.S. Pat. No. 3,475,836 (which issued to H. Braham on Nov. 4, 1969), U.S. Pat. No. 4,633,597 (which issued to J. Shiang on Jan. 6, 1987), and U.S. Pat. No. 4,760,651 (which issued to C. Pon-tzu on Aug. 2, 1988) contemplate shoe insoles having air pump structures included within a compressible insole, and having a check valve to insure movement of air in a particular direction therewithin. Each of these pumping devices relies upon the compressibility of portions of the insole to ultimately draw air into the insole during the noncompressive use periods, thereafter expelling the trapped air through air channels formed within the insole and upwardly through venting perforations to force air circulation within the shoe. Likewise, a shoe advertised under the name Taicher similarly included an insole insert portion having air inlet conduits with one-way check valves to permit the inlet of air into a collection space within the insole during noncompression use periods, with that trapped air being forced upwardly and outwardly into the shoe during compressive use periods.
While the above described, positive air flow ventilating insoles allegedly improve the air circulation within a particular shoe, heretofore there has not been available a readily interchangeable insole insert/shoe system which could simultaneously provide improved comfort for the wearer along with other beneficial features such as positive air ventilation, deodorization, anti-fungus protection, as well as improved blood circulation and support for the wearer's foot. While the prior devices have attempted to address individual ones of these benefits, none have been able to provide a combination of these benefits in a simple and efficient interchangeable structure.